Current synthetic orthopedic casting tapes are produced using curable resins coated on a substrate (fiberglass, polyester, or other synthetic or natural fabric). U.S. Pat. No. 4,411,262 (von Bonin et. al.) and U.S. Pat. No. 4,502,479 (Garwood et. al.) disclose the use of water-curable isocyanate-functional prepolymer in orthopedic casting tapes. After removal of the casting material from the storage pouch, especially after exposure to water used to initiate curing of the prepolymer, these resins are quite tacky until cured. This tackiness makes it difficult to mold the cast to the patient's limb as the resin tends to stick to the protective gloves worn by the cast applier. For example, after the rolls are wrapped but before they harden, some working time is necessary in order to mold the casts to fit the limb. This is accomplished by smoothing the cast with a gloved hand as well as holding the cast at certain points until it hardens. When a roll of tape coated with a tacky resin is used, molding the cast is difficult. The reason for this difficulty is that the glove sticks to the resin and when attempts are made to smooth the cast and form it, the layers of tape pull apart from each other thus requiring reforming of part of the cast.
It is believed that all curable resin coated orthopedic casting materials currently available commercially suffer from the above-noted problems.
U.S. Pat. No. 3,089,486 (Pike) discloses the use of beeswax as a release agent in the formation of an immobilizing orthopedic structure reinforced with a methacrylate polymer.
U.S. Pat. No. 4,100,122 (Kent) discloses the addition of crystalline wax to a mixture of transpolyisoprene and glass fibers to improve the flow characteristics of the composition during preparation, and the use of such compositions in moldable orthopedic devices.
U.S. Pat. No. 3,043,298 (Brickman et al.) discloses the addition of hydroxypropylmethyl-cellulose to a plaster of Paris bandage to be used as an orthopedic cast which gives the plaster of Paris a creamy consistency or texture when wet with water just prior to application.
U.S. Pat. No. 3,763,858 (Buese) discloses a composite material, useful as a surgical, medical, or orthopedic wrapping, which will adhere or cohere to another surface or to itself by the application of moderate pressure either at room temperature or at an elevated temperature and will be substantially nontacky to the touch until the application of such moderate pressure. The composite material comprises a cementitious core having bonded thereto a flexible, open cellular, resilient polymeric protective covering, the core having sufficient softness at the conditions of use to extend through the cells of the protective covering and become available at the outer surface thereof upon application of moderate pressure.
U.S. Pat. No. 3,630,194 (Boardman) discloses an orthopedic bandage comprising a flexible carrier supporting a solid water-soluble vinyl monomer selected from the group consisting of diacetone acrylamide and an isopropyl diacrylamide and mixtures thereof. The bandage is prepared for use by dipping in water in the presence of a catalyst for initiating polymerization of the vinyl monomer and then wrapping the body portion to be immobilized. The patent also discloses the use of inorganic fillers such as calcium sulfate, calcium carbonate, bentonite, or silica, to render the bandage less sticky and moderate any temperature rise during curing.
U.S. Pat. No. 4,454,873 (Laufenburg et al.) discloses an orthopedic cast material having a thermoplastic material and a quantity of polyethylene oxide applied thereto as an anti-block agent to prevent adherence of adjacent convolutions of the cast material when it is in the form of a roll and is immersed in hot water prior to being wrapped on a limb or body part of a patient. The polyethylene oxide can be in the form of a coating on the outer surface of the cast material or in the resin of the cast material. The patent implies that most, if not all of the polyethylene oxide is removed from the casting material when the casting material is removed from the hot water and that talc can be added to the resin to reduce tack.
U.K. Patent Application No. 2,092,606 (Potter et al.) discloses water hardenable splinting banadages comprising a flexible fabric carrying an isocyanate terminated prepolymer having a reaction functionality of two and a catalyst, which bandage is characterised in that the prepolymer is a water absorbing isocyanate terminated prepolymer and the catalyst is water soluble but insoluble in the prepolymer, wherein the prepolymer is derived from an ethylene oxide adduct. The application discloses that the catalyst is preferably an inorganic material which has an alkaline reaction in water, preferably a carbonate or bicarbonate.
A glove lubricant comprised of water, sorbitol, mineral oil and silicone fluid has been sold by 3M Co., St. Paul under the tradename Cast Cream with instructions to apply the lubricant to the gloves of one applying an isocyanate-functional prepolymer coated cast after wrapping of the cast but before molding of the cast to avoid having the exposed casting material adhere to the gloves of the one applying the cast.